Windward lifting centerboard



Aug. 26, 195 H. H. KIERSTEN 2,608,173

' WINDWARD LIFTING CENTERBOARD Filed Sept. 27, 1948 I 2 SHEETS-SHEET 1 28 Herbert Hinzie- Kersfen F/y. /0.

, INVENTOR.

Fig. 8 BY a, WW E Aug. 26, 1952 H. H. KERSTEN 2,608,173

WINDWARD LIFTING CENTERBOARD Filed Sept. 27, 1948 A 2 SHEETSSHEET 2 p /0 4 /0 64 Q- 5 Heme H/nzie Kerslen A INVENTOR.

\30 BY gyg mzy Altarnz s Patented Aug. 26, 1952 UNITED STATES PATENT OFFICE 2,608,173 V I I I WINDWARD LIFTING' CENTERBOARD Herbert Hinzie Kersten, Iowa City, Iowa Application September 27, 1948, Serial No. 51,346

, l A This invention relates to novel and useful improvements in appurtenances contiguouslto boats or other vessels. An object of this invention is to supply a device whereby a sail boat or othertypeof boat or vessel can be caused to be drawn windward when sailing or when being propelled, eliminating leeward drifting, and enablingthe real and apparent courses of the boat to coincide. thus allowing the hull of the boat to travel through the water on a straight forward course.

. The basic concept incorporated herewith includes the combination of a substantially identically constructed centerboard and rudder having a flexible center section with rigid leading and trailing edge members. The flexible center section-is curved or bent by the reaction of the water and boat to assume a contour similar to the contour of conventional airfoilthereby pro-- ducing' a lateral lift and resulting drag. The centerboard is pivoted at its trailing edge and so mounted that the leading edge has a limited range of lateral motions, thus when the boat is "pointing with the wind from the starboard bow, the leeward thrust on the boat causes the leading edge of the centerboard to move to the starboard side of the boat, at the same time permitting the midportion or flexible section of the centerboard to flex to the starboard, forming an under water surface with efficient upwind lifting tendency. By controlling the angle of incidence of the board and the degree of flexation or camber of the board, the drift tendencies of the hull are effectually counterbalanced. On the oposite tack the reverse process occurs.

Another purpose of this invention is to provide an extremely similar structurally defined rudder capable of flexation caused by hydrodynamic forces to counterbalance the undesired lateral having the invention applied thereto;

Figure 2 is a bottom view of the device shown in Figure 2; Figure 3 is a sectional view of the device shown 4 Claims. (01. 114-136) in Figure 1. visualizing the centerboard from a plan position; v

Figure 4 is a fragmentary view similar to that shown in Figure 3, showing a second operative position on the centerboard;

Figure 5 is a fragmentary plan view of the centerboard, showing a third operative position; Figure 6 is a sectional view taken substantially on the line 66 of Figure 1 and in the direction of the arrows; I I

' Figure '7 is a sectional view taken substantially on line 1-1 of Figure 1 and in the direction of the arrows;

Figure 8 is a longitudinal sectional view of the rudder forming a portion of the invention;-

Figure 9 is a sectional view taken substantially on the line 9-9 in Figure 1 and in the direction of the arrows; and

Figure 10 is a sectional view taken substantial? ly on the plane of section line l0l0 of Figure 6. The specific structure capable of performance of the objects of this invention is extremely simple. Accordingly, it is one of the intents of the present invention to supply such a device which is commercially feasible and practical, necessitating simplicity of structure. v

A conventional boat or similar'vessel is indicated, including a hull [0. An open ended upstanding housing I2 is provided in the hull, in communication with an opening 14 in the bottom thereof in order to accommodate a centerboard. A frame composed of heavy wire or the like is disposed in proximity to the housing I2 and is generally indicated at I6. This frame supports a pairof bearings I8 and 20 respectively having a guide arm of arcuate configuration seen at 22 slidably mounted therein. The guide 22 has a clamp 24 attached thereto, which is in turn secured to the upper portion of the front or leading'edge member 28 Viewing Figure '7 it is apparent that the leading edge member 28 is shaped to conform with and similar to a leading edge of an aircraft airfoil. A center section 30 of resilient material, such as rubber or the like is provided with a tongue 32 at the forward edge thereof, fitting in a complemental groove formed at the rear edge of the said leading edge member of rigid material 28. A number of pins or the like 34 may be supplied longitudinally of the forward portion of the center resilient or flexible section 30 in order to maintain the leading edge section or member 28 assembled with the center flexible section 30.

A trailing edge section 36 of rigid material is provided with a similar groove in order to match with a tongue 38 similar to the tongue 32. Of course, a number of the pins or other suitable fastening devices 34 are used for maintaining the trailing edge portion in assembled relation with the bendable or flexible section 30.

The rear portion of the trailing edge section 36 has an eye member 42 attached thereto, which is in turn secured to the frame 15, thereby pivotally mounting the trailing edge of the centerboard, while the leading edge thereof is free to move in a travel prescribed by the curvature of the guide 22.

As the hydrodynamic forces are transmittedin reaction with the hull of the vessel and more specifically, in reaction with the c'enterboard thereof, the centerboard assumes the. various devious shapes as is seen in Figures 3, 4 and 5 for the purpose of ultimately directing or guiding the vessel in the proper course.

To assist in carrying out this function, a rudder seen best in Figure 8 is provided-50f special structure. -A tiller 59 isdetachably mounted on the rudder guide bar 52, which in turnis suitably mounted in thehull of the vessel. A top. rigid member 54 of the said rudder is secured to the rudder guide rod or bar 52. A substantially U-shaped bracket 56 is attached at the extremities of its legs within suitable apertures in the section 54 of the rudder. U-shaped member also extend through suitable bores provided in the rigid-leading edge section 58 and the rigid trailing edge section-60 of the said rudder. The leading and trailing edges are suitably contoured as an air foil of an aircraft, attention being directed to Figure 9. 'Through the utility of the legs of the substantially U- shaped bracket, the said leading-edge section.

and trailing edge section may be pivotally associated with each other, being limited intheir pivotal travel by means of theflexible, resilient center section 62. This center section has grooves formedtherein (unnumbered) in order to accommodate tongues 64 and 66 respectively of the rigid sections 58 and 60. Suitable pins extend through the tongues and groovesmaintaining the leading edge section, trailing edge section and central section in the operative positionp w It is readily appreciated that the necessary flexing of the leading edge and trailing edgeas well, as center sections of the rudder 'may be effected as is effected. in. conjunction with the centerboard structure.

While there has been described andillustrated but a preferred form of the invention, "it is apparent that variationsmay be made Without departing from the spirit of the'invention.

Accordingly, limitation is sought only inaccordance with the scope of the following claims.

Having described the invention, What is claimed as new is: v

1. In a vessel having a hull and an open end The said legs. of the 4 housing mounted therein communicating with an opening in the bottom thereof, a frame associated with said housing, a centerboard extending through said housing, means on said frame for mounting said centerboard for horizontal swinging movement, said centerboard including a resilient section adapted to be bent by reaction of the hull opposed by resistance of the water supporting the hull, said mounting, means in- 'cluding avertical pivot inember attaching corresponding "ends of said centerboard and said frame together, an arcuate guide arm attached intermediate its ends to said centerboard adjacent the opposite end of said centerboard and means carried by the frame slidably receiving the ends of the" guide arm.

2.,The combination of claim 1 and a rigid leading edge member secured to said resilient section at one edge thereof and a rigid trailing edge member secured to said resilient section at the opposite edge thereof;

3; In a vesselhaving a hull and an open end housing mounted therein communicating with an opening in the bottom thereof, a frame associated with said housing, a centerboard extending through said housing, a smoothly curved guide arm slidably carried by said frame and overlying said centerboard, a vertical pivot securing said centerbcard to the frame, and a clamp rising from said centerboard and mounted on said arm,.said guidearm' being curved as an arc of a circle having its center at-said pivot. 4. The combination of claim 3 wherein said centerboard is composed of three sections including a rigid leadingsection, an intermediate resilient section and a rigid trailing section, and means securing adjacent sections together, the outer faces of said leading section and said trailing section being substantially flush with the, outer faces; of said resilient section.

HERBERT HINZIE KERS'IEIL,

REFERENCES CITED .The following references are of record 'in the; file of this patent:

' UNITED STATES PATENTS Norway Jan. 21, 19245 

